1. Field of the Invention
The present invention relates to a mechanical press and, in particular, a drive rod that is split at one or more places along its length and coupled together to form a rigid drive rod for motivating a slide or bed.
2. Description of the Related Art
Mechanical presses, for example, stamping presses and drawing presses, include a frame having a crown and a bed and a slide supported within the frame for motion toward and away from the bed. Such presses are widely used for stamping and drawing operations and vary substantially in size and available tonnage depending upon the attended use.
In the container art, the press workpiece or cup is usually formed of steel strip coated with a particular plastic layer. Various types of plastic are utilized to coat the steel. By carefully drawing and stamping the steel strip, containers with an interior plastic coating are created. These plastic liners are attached to the steel so that product contained within the formed can, e.g., liquid, does not touch the steel or metal.
In double action presses, a second slide replaces the bed and reciprocates in opposed relationship to the first slide. Traditional double action presses have slides driven by a plurality of crankshafts having various connecting arrangements connected to the slides. Typically, mechanical presses are fully assembled within the manufacturer's factory. For shipping purposes, the press is subsequently partially disassembled or "un-stacked." Normally, un-stacking entails removing the crown, upper slide, and drive rod from the base and crankshaft.
One form of current mechanical presses contains a continuous drive rod shaft attached between a crankshaft and an upper slide. The drive rod transfers rotational motion from the crankshaft to reciprocal motion which drives an upper slide upward and downward. To insure necessary tolerances and provide adequate strength, traditional drive rods are formed as a continuous drive rod shaft. Drive rod guide housings are installed around the upper and lower portions of the drive rod to assist in guiding the drive rod.
One problem with the continuous drive rod shaft design is that assembly and disassembly of the drive rod from a mechanical press requires the entire shaft to be handled. For example, when assembling a traditional press, the entire drive rod must be inserting through both the upper and lower guide housings at the same time. A continuous drive rod shaft is heavy and cumbersome making maneuvering of the drive rod difficult. Consequently, assembling and servicing of the press is complicated as a result of having to handle the entire shaft.
Yet another problem with current continuous drive rod shaft design is that the upper and lower guide housings are required to be perfectly in line with one another. Consequently, assembly of the press demands accurate alignment of the upper and lower guide housings.
Another problem with the current design is that replacement of a drive rod guide housing requires the entire drive rod to be removed. Removing the entire drive rod is further complicated by the fact that the upper slide or ram must be removed first. Therefore, if service or maintenance of the drive rod guide is required, both the entire drive rod and the upper slide must be removed. In addition, since current drive rods are composed of a single, continuous shaft, the entire drive rod shaft must be handled when removing the drive rod. Consequently, service or maintenance of the drive rod guide housing or the drive rod, itself, can be intricate and costly due to these limitations.
A further problem with the current continuous drive rod shaft design is that the entire drive rod must also be removed when the press is "un-stacked" for shipping purposes. Since the drive rod is a continuous shaft, the entire drive rod must be removed when "un-stacking" the press. As a result, there is an associated cost included within the cost of manufacturing, shipping, and reassembly of the mechanical press.